<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>flat 与 flatMap</title>
</head>
<body>
  
</body>
  <script>
      // const arr = [1,2,3,4,5,[1,2,3]]
      const arr02 = [
        1,
        2,
        3,
        4,
        [
          1,
          2,
          3,
          [
            1,
            2
          ]
        ]
      ]
      console.log(arr02.flatMap());
  </script>
</html>